BIGBADDAD

I have a 94 LS400 (240,000 miles), when I put it in drive it lunges forward. I think it might be motor mounts..Trans mount, but when I put it in gear and watch the engine it does not twist. Oh yea, I also need a good source for a key with the remote.
Thank you.
Mark

pfantom68

Does the car hesitate when you floor it from a complete stop? It is probably your trans mount, but it also may be the driveshaft joint, or both. At 240k, you probably need a new mount anyways, so do that, and pray that it takes away most of the lunging.

Key with a remote? Don't count on it. I was told they aren't reprogrammable, and a Lexus dealer will probably charge about $600 to replace the computer in the car and give you two new keys.

There is an aftermarket oem-replacement solution to this. I think avalon42 on here or Excelsior (can't remember) installed it, and said it worked quite well. You'd have to ask them about it.

Suneet

I have the same problem with mine, and I haven't bothered to fix it. I've got almost 210K now.

In regards to a key with a remote, I went ahead and went with a full aftermarket alarm system which works great.

black_LS

Where is your engine idling when you switch into D?

If it's too high, that might explain things, because when you switch it in D, it wants to shoot forward.

Suneet

Also note if you've got the AC running or not. And how warm the engine is etc.

pfantom68

My car used to do this when I had just bought it. Trust me, everything else was fine, so that means it's a trans mount and/or driveshaft failure.

The trans mount shouldn't cost more than like $60 shipped, and you can change it in your own garage with a jack, a couple jack stands, and a breaker bar.

kens97sto

Are you asking about just a key with the keyless function..or is the electronics in the car bad? Lexus told me the keyless key was $400, or a straight cut key was $75. They will need to see the title and a drivers licence that matches the name to give you the key. They will cut it based on the VIN #.

As to the lunging.. mine does this a bit too... more when its cold. I will be checking the trans mounts and driveline now.. thanks to those who posted about that.

Ken

Bali26

Key: http://www.sammywu.com/

You are welcome...

BIGBADDAD

I really appreciate all the info, you pretty much confirmed what I was thinking, as far as the drive shaft...I dont here a clunk, so I think it is a trans mount. My idle is about 600, and it doesnt happen in reverse. The key problem is...one of my keys work fine, the other does not, I think if I could replace the guts, or if I culd figure out how these things work (internally) I think I could fix it. I will probably end up going with a aftermarket set up, which I dont want to do?????????
Again THANK YOU.
This is a great forum.
Mark
P.S. It happens with, or without the A/C running. When it is warm it does'nt seem to be as bad, but yesterday I notice that if I let up on the accelerator before it shifts, that I can feel the car kinda lung back and forth, so I think it is another reason to look at the trans mount.
Thank you.
Mark

pfantom68

No problem Mark! Keep us updated on what happens after you change it.

BIGBADDAD

Will do. I think I will get it on a lift today...It just bugs me. But I love my car.
Thank you all
Mark

BIGBADDAD

Well its not a trans mount, motor mount or any other mount, I took it in to the dealer, and they found nothing, and of course they want a bunch of money to trouble shoot it. I will figure it out myself, or with a little help from this forum...I hope.
I steam cleaned my engine...don't ever do that, I ended up fouling a bunch of plugs, but all is good now.
Well if anyone comes up with an ideal that might fix my lunge, please let me know.
I wish you all a very merry Christmas.
Mark

lp_yang

can it be a sensor????

BIGBADDAD

I guess it could be a position sensor ...but which one. When the Lexus mech, had it up on the lift I watched him pry on all the mounts, and he looked at the drive line, he was baffled (about the lunge).
If anyone knows of a sensor that might cause this, please let me know.
Thank you.
Mark

avalon42

iTrader: (1)

My friend (who is a mechanic) worked on an Acura whose flywheel or torque converter? was loose, whenever they put the car in drive it would fly forward 2 feet. They took apart the transmission and flywheel, tightened everything up, problem went away.

Was your tranny ever out of the car or being serviced?